I've looked at the xyz:SP500 contract on hyperliquid and it's funding rate seems to be negative most of the time. Currently the annualized rate is around -0 to -2%, so if you hold a long position over a year you will roughly earn 1% on top (negative funding rate means short positions pay funding to long positions). This makes sense because the no-arbitrage principle requires this to be roughly in line with holding an actual SP500 basket and receiving dividends. And you don't pay interest on open positions, you are just holding a derivative and need to meet margin obligations - but you can leverage as much as you are comfortable with.